297 Каталог TESA 2014 Контрольно-измерительный инструмент и оборудование ENG Стр.O-4

Каталог TESA 2014 Инструмент и оборудование Стр. O-4 0297 ENG Lab2u

TESA ELECTRONIC LENGTH MEASURING EQUIPMENT Technology For the acquisition of measured values TESA offers a complete family of probes and measuring instruments for the most demanding applications. The probes supplied in standard execution do not need any form of adaptation. They function on the inductive half-bridge principle. The market offers other equipment using probes that partly operate on the principle of a differential transformer and these are known as LVDT (Linear Variable Differential Transformer) probes. TESA also offers a range of probes compatible with other electronic equipment using an adaptor and a connector depending on the origin of the equipment. A description of TESA standard half-bridge and LVDT probes is provided below. Standard half-bridge probes for TESA equipment OPERATING PRINCIPLE All Tesa electronic probes (value sensors) work based on the inductive principle with mechanical contact of the workpiece. they are fitted with a coil system inducing an alternating output voltage that depends on the the position of the ferro magnetic core. When symmetrically positioned i.e. at electrical zero no voltage is impressed. A move of the core which may be attached to the measuring bolt while the measurand is being taken causes the inductance to change. This change generates a signal that is amplified and rectified before being displayed and further output. Depending on the instrument type the analogue signal will be shown on a voltmetre or a numerical display after a digital transformation. Unambiguous assessment of the measurand (at bolt position) to the signal (displayed value) is the main characteristic of analogue value acquisition. One of its distinct advantages lies in the value primarily displayed which will be reproduced in the event of a power cut (switch-off or power failure). Inductive measuring S Travel U Output current 0 Electrical zero L Linearity range Lf Linearity error TESA Standard Half-Bridge Probes for TESA Electronic Equipment These probes have two serial coils with middle output mounted side by side which are energized by a sinusoidal alternation signal at 13 kHz. Both are linked together to a Wheatstone bridge over an additional halfbridge. Wiring plan of half-bridge probes TESA LVDT Probes These probes are based on a Linear Variable Differential Transformer (LVDT). They have three coils i.e. one primary coil being energized by a sinusoidal alternation at 5 kHz and two secondary coils connected in opposite phase which generate the output current proportional to the measuring travel. Available upon request. Wiring plan of LVDT probes